caretta notes

tracer.go

// https://github.com/groundcover-com/caretta/blob/b03437eadacb683c9f4170ccb6f7acd9efeb12af/pkg/tracing/probes.go

func LoadProbes() (Probes, *ebpf.Map, error) {
	objs := bpfObjects{}
	err := loadBpfObjects(&objs, &ebpf.CollectionOptions{})
	if err != nil {
		var ve *ebpf.VerifierError
		if errors.As(err, &ve) {
			fmt.Printf("Verifier Error: %+v\n", ve)
		}
		return Probes{}, nil, fmt.Errorf("error loading BPF objects from go-side. %v", err)
	}
	log.Printf("BPF objects loaded")

	// attach a kprobe and tracepoint
	kp, err := link.Kprobe("tcp_data_queue", objs.bpfPrograms.HandleTcpDataQueue, nil)
	if err != nil {
		return Probes{}, nil, fmt.Errorf("error attaching kprobe: %v", err)
	}
	log.Printf("Kprobe attached successfully")

	tp, err := link.Tracepoint("sock", "inet_sock_set_state", objs.bpfPrograms.HandleSockSetState, nil)
	if err != nil {
		return Probes{}, nil, fmt.Errorf("error attaching tracepoint: %v", err)
	}
	log.Printf("Tracepoint attached successfully")

	return Probes{
		Kprobe:     kp,
		Tracepoint: tp,
		BpfObjs:    objs,
	}, objs.Connections, nil
}